In industrial control applications, various control circuits are formed in functional modules and a plurality of control modules is removably installed in a control system, to provide the system with different control functions. In order to satisfy such needs, i.e., the need of adding or removing particular module from time to time, each functional modules is provided with necessary connector modules, with a same number of electrical contacts at identical positions among all connector modules. In particular, the various functional modules form a flat cassette, with their electrical contacts formed in both sides of the flat cassettes at respectively corresponding positions, so that a cassette can establish electrical connections with another adjacent to either side of the other at the electrical contacts, in order to exchange signals or power.
U.S. Pat. No. 5,716,241 disclosed an “I/O Device for a Data Bus” including a connector module having such modularized connectivity. The connector module is accommodated in a module cassette.
In order to support connections of function modules, the industry has developed a connector module. The connector module has main body in the shape of a flat cassette, with a same number of contact pins at corresponding positions in its both sides, such that one other connector module, also in the shape of a cassette, can establish electrical connections at either side of the cassette. The contact pins of a pair form a T shape, with two pins respectively extended to both sides and a third pin extended in a perpendicular direction. As a general design, the third pin includes two elastic legs configured to clip an external connector, such as one of the goldfingers provided in a circuit board having a functional module. When the external connector is inserted in the third connector, the functional module in connection with the external connector establishes electrical contact with the T-shaped connector piece. That is, when no external connector is inserted, the T-shaped connector piece conducts laterally, called short circuit; when the external connector is inserted, the T-shaped connector piece additionally conducts the functional module in connection with the external connector. With such a connector structure, the functional module may form a “series” or “parallel” connection with other functional modules, depending on the design of the functional modules.
WO 00/62376A1 disclosed an “Input/Output Device Having Removable Module” that has a connector module provided with such function. A T-shaped connector piece for use in the connector module is also disclosed.
US 2013/0027890 disclosed a “Connection Module Being Capable of Serving a Bus” that uses a plurality of connector modules to form a bus structure. This connection module enables the so-called “bus” connection of the functional modules.
Providing a multiple modal connection function and changing the interconnection among contact pins by inserting a foreign object in a group of connectors were disclosed in U.S. Pat. No. 7,402,058, “Plug Connector with Short Circuit Contacts.”
In response to the urgent needs for multiple modal functional modules in the industry, connector modules that support multi-modal connection functions are developed. The multi-modal connector modules provide a plurality of connection modes, for the functional module suppliers' selection. The multi-modal connector modules may be used in most functional modules, to connect other functional modules where varies electrical connection modes are used.